Photographic developer



United States Patent PHOTOGRAPHIC DEVELOPER Isaac Oretzky, New York, N.Y.

No Drawing. Application July 22, 1954, Serial No. 445,190

2 Claims. (Cl. 95-88) The present invention relates generally to the artof photography, and in particular it relates to an improved fine graindeveloper of photographic film.

In the art of developing photographic film, it is highly desirable thatthe same developing solution be capable of use for films exposed underwidely diverse conditions. Ordinarily, the developer must compromisebetween developing speed, life of solution, and proper imagecharacteristics, i. e., shadow detail, contrast, grain size. To thesecompromises must be added the sacrifice of overexposed and under-exposedfilm.

The prime object of this invention is to provide a developer capable ofdeveloping badly under-exposed pictures in a roll of film withoutadversely overdeveloping pictures in the roll taken at proper exposures.

Briefly stated, this invention comprises a specific developerformulation capable of carrying out the foregoing object.

Using this developer the speed of photographic film is increased from 12to 20 times, depending upon the nature of the light. In natural lightunder the most adverse conditions, e. g. during a cloudy late afternoon,when the exposure meter with the slide out registers in the lowestblocks, this developer will have the elfect of increasing the speed ofthe film about 12 times. Under artificial (tungsten) light, the speed isincreased up to 20 times or more. This characteristic is mostadvantageous when a series of pictures taken on a roll of film includeseveral taken outdoors in natural light and others taken indoors underlimited light (such as provided by ordinary house lamps). All thepictures will be developed into usable negatives. Thus the substantialdifferences in lighting facilities available during the shooting of asequence of pictures on a single roll of film are largely equalized ifthe exposed film is handled in the developing solution of thisinvention. The weakest latent image will be brought out withoutsimultaneously burning a strong image.

The specific formulation of the developer is as follows:

This developer is very stable and does not deteriorate. It will keep atleast one year to one and one'half years in a stoppered bottle. Asolution of developer which has already been used will nevertheless bestable and usable for about eight months. One quart of the developer can2,757,09l Patented July 31, 1956 ice develop about fourteen standardrolls of film approximately eighty inches each.

While the above formula produces the best results, it will be understoodthat some of the ingredients listed may be replaced by other chemicals.For example, benzoic acid can be used in a place of sodium bisulfitewithout affecting the quality of the developer. In place of the glycin,para-amino-phenol hydrochloride could be used. However, glycin has thequality of providing a desirable staining effect to the developer and isa better preservative.

The developing period which produces the most favorable results is 911minutes at room temperature, e. g. The developed negative is clear andsharp, and is capable of enlargement up to 19 times without occurrenceof strong or disfiguring grain. Under optimum conditions of uniformtemperature in the developer, the short stop and the hypo; and a dryingtime of about 30 minutes the negative can be enlarged 20 times withoutshowing objectionable grain. Film which is overdeveloped, i. e., left inthe developer too long, will nonetheless not be mottled or disfigured.The grain Will be quite fine and uniform, and unobjectionable.

Following is a specific example of the results produced by thisdeveloper. Two pictures were taken under artificial light on Kodak SuperXX Film at one-tenth of a second exposure with a lens opening of F 5.6.The light consisted of an overhead 150 watt bulb suspended from theceiling at a location about 13 feet from the subject, and a watt bulb ina shaded lamp. The exposure meter registered nothing. When developed,each picture came out with full clarity and fine grain.

In addition to having much faster development time than the presentlyavailable fine grain developers, the present developer producednegatives having much better detail and much sharper, clearer images.Whereas this invention has been described in detail with respect to aspecific embodiment thereof, it is to be understood that various changesmay be made therein on the basis of the teachings hereof, by thoseskilled in the art, without departing from the protective scope of thefollowing claims.

Having thus described the invention, What is claimed is:

1. A photographic developing composition containing the followingingredients in the following proportions:

Maximum Minimum 1. 96 2. 196 160 3. 7 3 4. Hydroquinone gr 150 55 5.Glyein (parahydroxyphenyl glycine). g.. 14 4 6. Sodium Carbonate 322 757. Acetone 644 8. Triethan0lamine. 644 155 9. Water to make one-halfgallon so 2. A photographic developing composition containing thefollowing ingredients in the following proportions:

No references cited.

1. A PHOTOGRAPHIC DEVELOPING COMPOSITION CONTAINING THE FOLLOWINGINGREDIENTS IN THE FOLLOWING PROPORTIONS:
 1. ELON GR 150 96
 2. SODIUMSULFITE G 196 160
 3. SODIUM BISULFITE G 7 3
 4. HYDROQUINONE GR 150 55 5.GLYEIN (PARAHYDROXYPHENYL GLYCINE) G 14 4
 6. SODIUM CARBONATE GR 322
 757. ACETONE GR 644 155
 8. TRIETHANOLAMINE GR 644 155
 9. WATER TO MAKEONE-HALF GALLON SOLUTION.